On Mon, Feb 15, 2016 at 08:04:04PM +0000, Will Deacon wrote: [...]
> On Wed, Feb 03, 2016 at 06:12:00PM +0100, Jan Glauber wrote: > > + cpu_pmu->event_mask = 0xffff; /* ARMv8.1 extended events */ > > + else > > + cpu_pmu->event_mask = ARMV8_EVTYPE_EVENT; > > ... although can't we just update ARMV8_EVTYPE_EVENT to be 0xffff now? > AFAICT, that just eats into bits that used to be RES0, so we shouldn't > see any problems. That should make your patch *much* simpler! That would of course be easier, but I just can't assess the implications. Probably I'm missing something but to me it looks like the event mask is the only verification we do for the user-space selectable events. Is it safe for implementations that only support 0x3ff events to allow access to the whole 0xffff range? What memory would be accessed for non-existing events? Jan > Will
